public RPCResult <bool> PacketReceived(byte[] packet, int dev_no, int payload_offset,
int payload_len, p_addr src)
{
/* Parse the provided packet */
byte type = packet[payload_offset];
byte code = packet[payload_offset + 1];
uint csum = ipv4.calc_checksum(packet, payload_offset, payload_len);
if (csum != 0)
{
System.Diagnostics.Debugger.Log(0, null, "Received ICMP message with " +
"invalid checksum " + csum.ToString("X4"));
return(false);
}
ushort ident = net.ReadWord(packet, payload_offset + 4);
ushort seq = net.ReadWord(packet, payload_offset + 6);
System.Diagnostics.Debugger.Log(0, null, "ICMP message received from " +
src.ToString() + ": type: " + type.ToString() + ", code: " +
code.ToString() + ", ident: " + ident.ToString() + ", seq: " +
seq.ToString());
return(true);
}
public void TransmitEthernetPacket(byte[] packet, int dev_no, int payload_offset,
int payload_len, p_addr dest, ushort etype)
{
/* Build an ethernet packet from the higher level packet passed to us.
*
* First, decide if we have enough space in the original buffer to
* build the packet around. We need 14 bytes before the packet and
* optionally 4 bytes after if the device doesn't add FCS.
*
* TODO: add support also for padding here */
var nd = devs[dev_no];
bool need_new_buf = false;
int header_len = 14;
if (payload_offset < header_len)
{
need_new_buf = true;
}
int crc_len = 0;
if (nd.dev_appends_crc_on_tx == false)
{
crc_len = 4;
}
if (packet.Length < payload_offset + payload_len + crc_len)
{
need_new_buf = true;
}
if (need_new_buf)
{
byte[] new_buf = new byte[header_len + crc_len + payload_len];
for (int i = 0; i < payload_len; i++)
{
new_buf[header_len + i] = packet[payload_offset + i];
}
payload_offset = header_len;
packet = new_buf;
}
// Add in the header
payload_offset -= header_len;
payload_len += header_len;
// dest
var d = dest as HWAddr;
if (d == null)
{
System.Diagnostics.Debugger.Log(0, null, "TransmitEthernetPacket: "
+ "dest is not a hardware address: " + dest.ToString());
return;
}
for (int i = 0; i < 6; i++)
{
packet[payload_offset + i] = d.MAC[i];
}
// src
for (int i = 0; i < 6; i++)
{
packet[payload_offset + 6 + i] = nd.HWAddr.MAC[i];
}
// ethertype
packet[payload_offset + 12] = (byte)((etype >> 8) & 0xff);
packet[payload_offset + 13] = (byte)(etype & 0xff);
// TODO: pad if required
if (nd.dev_pads_on_tx == false && payload_len + crc_len < 64)
{
System.Diagnostics.Debugger.Log(0, null, "TransmitEthernetPacket: "
+ "packet too short and device does not automatically pad");
return;
}
// TODO: add FCS if required
if (nd.dev_appends_crc_on_tx == false)
{
System.Diagnostics.Debugger.Log(0, null, "TransmitEthernetPacket: "
+ "device does not automatically add FCS");
return;
}
// Send packet
nd.s.TransmitPacket(packet, dev_no, payload_offset, payload_len, dest);
}
public RPCResult <HWAddr> ResolveAddress(int dev_no, p_addr addr)
{
/* Get the appropriate dictionary */
var prot_dict = GetProtocolDictionary(dev_no, addr.EtherType);
/* If the cache contains the value we need, then we can use it
* directly, otherwise we need to send a request for it */
HWAddr ret;
if (prot_dict.TryGetValue(addr, out ret) == true)
{
System.Diagnostics.Debugger.Log(0, null, "Resolving " +
addr.ToString() + " from cache to " + ret.ToString());
return(ret);
}
/* We need to send a ARP request out to the network, then respond to
* the reply. Unfortunately, messages sent to the arp subsystem are
* processed sequentially, therefore the reply will never be processed
* until the current function exits. To get around this, we tell the
* Invoke mechanism not to return from the synchronous call until
* we have that response */
var e = CurrentMessage;
e.EventSetsOnReturn = false;
/* Send the request */
switch (addr.EtherType)
{
case 0x0800:
/* IPv4 */
HWAddr sha = net.devs[dev_no].HWAddr;
IPv4Address spa = net.devs[dev_no].addresses[0x0800] as IPv4Address;
IPv4Address tpa = addr as IPv4Address;
byte[] pkt = new byte[100];
int packet_offset = 32;
int packet_len = 0;
pkt[packet_offset + packet_len++] = 0x00; // HTYPE
pkt[packet_offset + packet_len++] = 0x01;
pkt[packet_offset + packet_len++] = 0x08; // PTYPE
pkt[packet_offset + packet_len++] = 0x00;
pkt[packet_offset + packet_len++] = 0x06; // HLEN
pkt[packet_offset + packet_len++] = 0x04; // PLEN
pkt[packet_offset + packet_len++] = 0x00; // OPER
pkt[packet_offset + packet_len++] = 0x01;
// SHA
for (int i = 0; i < 6; i++)
{
pkt[packet_offset + packet_len++] = sha.MAC[i];
}
// SPA
for (int i = 0; i < 4; i++)
{
pkt[packet_offset + packet_len++] = spa.Octets[i];
}
// THA
for (int i = 0; i < 6; i++)
{
pkt[packet_offset + packet_len++] = 0;
}
// TPA
for (int i = 0; i < 4; i++)
{
pkt[packet_offset + packet_len++] = tpa.Octets[i];
}
net.TransmitEthernetPacket(pkt, dev_no, packet_offset,
packet_len, HWAddr.Multicast, 0x0806);
break;
}
// Store this request
GetPendingRequestList(dev_no, addr.EtherType, addr).Add(e);
// Return null for now until we actually get a result
return(null);
}